UNCONTROLLED FLIGHT INTO TERRAIN: LOSS OF SPEED AWARENESS
The FAA desires that all aircraft maintain a minimum 30% speed buffer above stall in all flight conditions.
The exception to this is during final approach when under certain conditions it may be permissible to go as low as 20% above stall speed, or 1.2 Vso.
A large percentage of GA accidents occur during clean wing maneuvering either after takeoff during climb, or entering the traffic pattern and maneuvering.
When a pilot becomes distracted and allows speed to decay, GA has no audible or visual warning to alert the pilot that they have transgressed this sacred 30% area.
The stall horn does activate very close to the actual stall but in most cases, it is too late.
A spin often follows an aerodynamic stall. Most of these accidents happen below 1000 AGL where even the most proficient pilot in the world would have no chance of completing a spin recovery prior to impact.
PREVENTION is the only real tool available.
Be aware of that 30% by placarding Vs1 x 1.404 for your aircraft right on the face of your airspeed indicator! Studies have shown that this simple indicator is almost 100% effective in increasing a pilot’s awareness of where this 30% clean buffer boundary is.
SOLUTION:
Placard your ASI with a DMMS marker and practice referring to it often while in the pattern. Take immediate corrective action any time you are in flight below DMMS speed and not on final approach. DMMS awareness leads to the PREVENTION of low speed condition fatal accidents.
SAMPLE ACCIDENT REPORT: #1
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The sport pilot's failure to maintain adequate airspeed during landing in crosswind conditions resulting in an aerodynamic stall. Accident Number: ERA10LA158.
SAMPLE ACCIDENT REPORT: #2
The National Transportation Safety Board determines the probable cause(s) of this accident to be: An engine malfunction for undetermined reasons and the subsequent loss of control, due to the pilot's improper decision to maneuver the airplane below minimum controllable airspeed and his improper response to the loss of engine power. Accident Number: CEN18FA116.
SAMPLE ACCIDENT REPORT: #3
The pilot’s failure to maintain airspeed during a steep turn after takeoff, resulting in an exceedance of the airplane’s critical angle of attack and a subsequent accelerated stall at an altitude too low for recovery. NTSB Accident Number CEN18FA147.